Efect of Shape, Surface Modifcation and Concentration of Al2O3 Nanoparticles on Breakdown Performance of Transformer Oil

Muhammad Rafq,Yuzhen Lv,Chengrong Li 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.1

The Al2O3 nanoparticles (NPs) with favorable features were prepared in our lab to develop transformer oil/paper insulation system with better insulation performance. The nanofuids (NFs) were prepared with diferent shapes (nanorods, nanoplates), surface modifcations (oleic acid, C2, C18) and concentrations (0.6 g/L, 0.8 g/L, 1.2 g/L) of Al2O3 NPs. The positive lightning impulse (LI) breakdown voltages (VBDs) of mineral oil were improved by 1.11 times with nanorod shape, oleic acid surface modifcation and 0.8 g/L concentration of NPs. The efects of Al2O3 NPs with diferent gap distances on insulating properties of NFs under LI voltage were examined. It was noted that after Al2O3 NPs suspension, the positive LI VBDs of transformer oil (TO/MO) were enhanced but the negative LI VBDs of were decreased. The signifcant improvement in insulating performance of NFs is interpreted in light of electron traps theory. It was found that suspended NPs can enhance the shallow trap desity. The generated electrons would lose their kinetic energy through repeatedly trapping and de-trapping process, leading to decline in elcetron mobility. The higher trap density of NPs will lower average energy, and lower mobility of electrons are obtained. The electrons with lower energy are easy to be captured by those molecules with high electron afnity, and be converted into negative space charges. These negative space charge decreases the electrical feld strength at the front of positive streamer and therefore reduce the propagating velocity of positive streamer.

중국에서의 소비자 불안과 소비자 행동: 향수 감성의 매개 효과를 중심으로

리위쩐 ( Li Yuzhen ),김우형 ( Kim Woohyoung ),조용석 ( Cho Yongseok ) 현대중국학회 2020 現代中國硏究 Vol.22 No.3

최근 국가적 불안이 현대 사회에서 가장 중요한 사회심리학적 현상이 되었다. 저자들은 소비자 행동에 있어 소비자 불안의 영향을 끼치는 메커니즘에 대해 실증분석을 수행하였다. 본 논문은 SPSS 25.0과 AMOS 21.0 및 구조방정식모델링을 이용해 348개의 유효한 샘플을 실증분석에 적용하였다. 실증분석 결과 소비자 불안은 향수 소비자 행동에 긍정적 영향을 주었다. 소비자들이 높은 수준의 향수를 갖고 있을수록 그들의 소비결정과 소비 정체성이 높은 수준을 유지하였다. 또한 향수는 사회적 불안, 성공, 그리고 향수 소비자 의사결정과 정체성에 있어 긍정적 관계의 매개효과를 보였다. Nowadays, national anxiety has become one of the most significant psychosocial phenomena in current society. We conduct empirical research on the mechanism of the influence of consumer anxiety on consumer behavior. This paper applies an empirical analysis to 348 valid samples of the survey with structural equation modelling and related assumptions through SPSS25.0 and AMOS21.0. Consumer anxiety has a positive impact on nostalgic consumer behavior. When customers have a higher level of nostalgia, their consumption decision and consumption identity will maintain at a high level. Nostalgia mediates the positive relationship between social anxiety, achievement and development anxiety in consumer anxiety on nostalgic consumer decision-making and identity.

Neutrophil-inspired photothermo-responsive drug delivery system for targeted treatment of bacterial infection and endotoxins neutralization

Chengnan Li,Yingying Gan,Zongshao Li,Mengjing Fu,Yuzhen Li,Xinran Peng,Yongqiang Yang,Guo‑bao Tian,Yi Yan Yang,Peiyan Yuan,Xin Ding 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background P. aeruginosa, a highly virulent Gram-negative bacterium, can cause severe nosocomial infections, and it has developed resistance against most antibiotics. New therapeutic strategies are urgently needed to treat such bacterial infection and reduce its toxicity caused by endotoxin (lipopolysaccharide, LPS). Neutrophils have been proven to be able to target inflammation site and neutrophil membrane receptors such as Toll-like receptor-4 (TLR4) and CD14, and exhibit specific affinity to LPS. However, antibacterial delivery system based on the unique properties of neutrophils has not been reported. Methods A neutrophil-inspired antibacterial delivery system for targeted photothermal treatment, stimuli-responsive antibiotic release and endotoxin neutralization is reported in this study. Specifically, the photothermal reagent indocyanine green (ICG) and antibiotic rifampicin (RIF) are co-loaded into poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NP-ICG/RIF), followed by coating with neutrophil membrane to obtain antibacterial delivery system (NM-NP-ICG/RIF). The inflammation targeting properties, synergistic antibacterial activity of photothermal therapy and antibiotic treatment, and endotoxin neutralization have been studied in vitro. A P. aeruginosa-induced murine skin abscess infection model has been used to evaluate the therapeutic efficacy of the NM-NP-ICG/RIF. Results Once irradiated by near-infrared lasers, the heat generated by NP-ICG/RIF triggers the release of RIF and ICG, resulting in a synergistic chemo-photothermal antibacterial effect against P. aeruginosa (~ 99.99% killing efficiency in 5 min). After coating with neutrophil-like cell membrane vesicles (NMVs), the nanoparticles (NM-NP-ICG/RIF) specifically bind to inflammatory vascular endothelial cells in infectious site, endowing the nanoparticles with an infection microenvironment targeting function to enhance retention time. Importantly, it is discovered for the first time that NMVs-coated nanoparticles are able to neutralize endotoxins. The P. aeruginosa murine skin abscess infection model further demonstrates the in vivo therapeutic efficacy of NM-NP-ICG/RIF. Conclusion The neutrophil-inspired antibacterial delivery system (NM-NP-ICG/RIF) is capable of targeting infection microenvironment, neutralizing endotoxin, and eradicating bacteria through a synergistic effect of photothermal therapy and antibiotic treatment. This drug delivery system made from FDA-approved compounds provides a promising approach to fighting against hard-to-treat bacterial infections.

Input Disturbance Suppression for Port-controlled Hamiltonian System via the Internal Model Method

Changsheng Li,Yuzhen Wang 제어·로봇·시스템학회 2013 International Journal of Control, Automation, and Vol.11 No.2

This paper investigates the input disturbance suppression problem for nonlinear Port-Controlled Hamiltonian (PCH) system and presents a number of new results on the controllers design via the internal model approach. Different from the existing results on this topic we consider two cases. Firstly, the case of the disturbance generated from a linear Hamiltonian system acts through a channel other than the input channel is studied by adopting a method of decomposing the control into two parts and designing an internal model to zero the effect of the exogenous disturbance. Secondly, the case of the disturbance generated from a bounded nonlinear exosystem is studied by presenting a procedure of designing a nonlinear internal model to cancel the effect of the disturbance under two fundamental as-sumptions. Moreover, to further improve the suppression, a more effective internal model is also de-signed under less hypotheses. Finally, as an useful application, a corollary is presented by applying these results on PCH system to general nonlinear affine system. Simulations of a third-order synchro-nous generator model with disturbance generated from a nonlinear exosystem show the effectiveness of the designed internal model.

LINC00174 Facilitates Proliferation and Migration of Colorectal Cancer Cells via MiR-3127-5p/ E2F7 Axis

( Yuhong Ma ),( Yuzhen Li ),( Yuanyuan Tang ),( Ning Tang ),( Dengke Wang ),( Xiaofei Li ) 한국미생물 · 생명공학회 2021 Journal of microbiology and biotechnology Vol.31 No.8

The literature indicates that LINC00174 promotes the growth of colorectal cancer (CRC) cells, but its research needs to be enriched. We tried to explore the function and mechanism of LINC00174 in CRC cell proliferation and migration. Bioinformatics analysis predicted the binding relationship and expressions of lncRNA, miRNA and mRNA. Clinical study analyzes the relationship between LINC00174 and clinical data characteristics of CRC patients. The expressions of LINC00174, miR-3127-5p and E2F7 were verified by RT-qPCR, and the combination of the two was verified by dual luciferase analysis and RNA immunoprecipitation as needed. Western blot was used to detect the expression of EMT-related protein and E2F7 protein. Functional experiments were used to evaluate the function of the target gene on CRC cells. LINC00174 was up-regulated in CRC clinical samples and cells and was related to the clinical characteristics of CRC patients. High-expression of LINC00174, contrary to the effect of siLINC00174, promoted cell viability, proliferation, migration and invasion, up-regulated the expressions of N-Cadherin, Vimentin, E2F7, and inhibited the expression of E-Cadherin. MiR-3127-5p was one of the targeted miRNAs of LINC00174 and was down-regulated in CRC samples. In addition, miR-3127-5p mimic partially reversed the malignant phenotype of CRC cells induced by LINC00174. Besides, E2F7 was a target gene of miR-3127-5p, and LINC00174 repressed miR-3127-5p to regulate E2F7. Our research reveals that LINC00174 affected the biological characteristics of CRC cells through regulated miR-3127-5p/ E2F7 axis.

MAP3Kθ1 is Involved in Abscisic Acid Signaling in Drought Tolerance and Seed Germination in Arabidopsis

Liguo Jia,Yuzhen Chen,Mingshou Fan,Wenrao Li,Jianhua Zhang 한국식물학회 2020 Journal of Plant Biology Vol.63 No.1

Mitogen-activated protein kinase cascades play pivotal roles in mediating environmental stress responses and plant development. In this study, a loss-of-function mutant of Arabidopsis, map3kθ1, exhibited wider stomatal openings, reduced root elongation, and increased seed germination rate compared with its wild type under exogenous abscisic acid (ABA) treatment. MAP3Kθ1 encodes a MAP kinase kinase kinase (MAP3K) with unknown function. Two overexpression lines of MAP3Kθ1 exhibited inhibited seed germination and narrowed stomata, which were aggravated by ABA treatment. Upregulation of MAP3Kθ1 also resulted in stronger drought tolerance, whereas map3kθ1 was more sensitive to water defciency, partially due to diferences in the water-holding capacity of leaves. The MAP3Kθ1-overexpressing lines also showed a greater ability to maintain root elongation under exogenous ABA. Expression of MAP3Kθ1 was inhibited by ABA, H2O2, and methyl viologen treatments in roots. The MAP3Kθ1-overexpressing lines accumulated more ABA by promoting its biogenesis and inhibiting its catabolism, whereas the map3kθ1 mutant accumulated less ABA, compared with wild-type plants. These fndings indicate that MAP3Kθ1 promotes ABA accumulation to regulate stomatal movement, root elongation, and seed germination, while the ABA–H2O2 signaling module inhibits MAP3Kθ1 expression through feedback regulation.

Interval non-probabilistic time-dependent reliability analysis of boom crane structures

Yang Ruigang,Li Wenzhao,Zhao Guangli,Liu Yuzhen,Jing Weichen 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.2

The reliability of boom crane structure determines the safety and performance of the whole machine. Due to the sample information of uncertain parameter is lacking, nonprobabilistic reliability of boom crane structure under the condition of limited samples is studied. Considering the time dependent deterioration of structure resistance and the load time effect, the time-dependent uncertain parameters of boom structures are comprehensively analyzed. A time-dependent reliability model of boom structures based on interval non-probabilistic is proposed. Based on the theory of interval non-probabilistic time-varying reliability, an engineering example is analyzed by using VC++ programming. The influence of different weight and uncertain parameters on the structure reliability of the boom is analyzed. The results show that the resistance, attenuation coefficient, average resistance and non-probabilistic time-varying reliability indicators of the boom structure attenuate seriously after decades. The conclusion verifies the scientific of the proposed method on the time accumulation effect.

Molecular characterization and immunohistochemical localization of a mitogen-activated protein kinase, Accp38b, from Apis cerana cerana

Zhang, Liang,Meng, Fei,Li, Yuzhen,Kang, Mingjiang,Guo, Xingqi,Xu, Baohua Korean Society for Biochemistry and Molecular Biol 2012 BMB Reports Vol.45 No.5

The p38 mitogen-activated protein kinase (MAPK) is involved in various processes, including stress responses, development, and differentiation. However, little information on p38 MAPK in insects is available. In this study, a p38 MAPK gene, $Accp38b$, was isolated from $Apis$ $cerana$ $cerana$ and characterized. The quantitative real-time PCR (Q-PCR) analysis revealed that $Accp38b$ was induced by multiple stressors. Notably, the expression of $Accp38b$ was relatively higher in the pupae phase than in other developmental phases. During the pupae phase, Accp38b expression was higher in the thorax than in the head and abdomen and higher in the fat body than in the muscle and midgut. Immunohistochemisty showed significant positive staining of Accp38b in sections from the brain, eyes, fat body, and midgut of $A.$ $cerana$ $cerana$. These results suggest that Accp38b may play a crucial role in stress responses and have multiple aspects function during development.

Alpha radionuclide-chelated radioimmunotherapy promoters enable local radiotherapy/chemodynamic therapy to discourage cancer progression

Jiajia Zhang,Feize Li,Yuzhen Yin,Ning Liu,Mengqin Zhu,Han Zhang,Weihao Liu,Mengdie Yang,Shanshan Qin,Xin Fan,Yuanyou Yang,Kun Zhang,Fei Yu 한국생체재료학회 2022 생체재료학회지 Vol.26 No.4

Background: Astatine-211 is an α-emitter with high-energy α-ray and high cytotoxicity for cancer cells. However, the targeted alpha therapy (TAT) also suffers from insufficient systematic immune activation, resulting in tumor metastasis and relapse. Combined immune checkpoint blockade (ICB) with chemodynamic therapy (CDT) could boost antitumor immunity, which may magnify the immune responses of TAT. This study aims to discourage tumor metastasis and relapse by tri-model TAT-CDT-ICB strategy. Methods: We successfully designed Mn-based radioimmunotherapy promoters (211At-ATE-MnO2-BSA), which are consisting of 211At, MnO2 and bovine serum albumin (BSA). The efficacy of 211At-ATE-MnO2-BSA was studied as monotherapy or in combination with anti-PD-L1 in both metastatic and relapse models. The immune effects of radioimmunotherapy promoters on cytotoxic T lymphocytes and dendritic cells (DCs) were analyzed by flow cytometry. Enzymelinked immunosorbent assay and immunofluorescence were used to explore the underlying mechanism. Results: Such radioimmunotherapy promoters could not only enhance the therapeutic outcomes of TAT and CDT, but also induce robust anti-cancer immune activity by activating dendritic cells. More intriguingly, 211At-ATE-MnO2-BSA could effectively suppress the growths of primary tumors and distant tumors when combined with immune checkpoint inhibitors. Conclusions: The tri-model TAT-CDT-ICB strategy provides a long-term immunological memory, which can protect against tumor rechallenge after eliminating original tumors. Therefore, this work presents a novel approach for TATCDT-ICB tri-modal cancer therapy with repressed metastasis and relapse in clinics.

An Enhanced Biometric-Based Three Factors User Authentication Scheme for Multi-server Environments

Youping Lin,Kaihui Wang,Baocan Zhang,Yuzhen Liu,Xiong Li 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.1

Authentication is an important and basic security service for many network based applications, which allows the registered user access remote services after the validity of his/her identity is verified by the remote server. Password, smart card and biometric are three frequently used factors in authentication, and some remote user authentication schemes for different environments had been presented based on these factors by researchers. Recently, Baruah et al. pointed out the weaknesses of Mishra et al.’s three factors user authentication scheme for multi-server environments, and they proposed an enhanced scheme. They claimed that their scheme has many security features and can resist some common attacks. However, based on our analysis, Baruah et al.’s scheme cannot resist stolen smart card attack, cannot protect user’s anonymity, and it is also vulnerable to Denial of Service attack. In this paper, an enhanced three factors user authentication scheme for multi-server environments based on fuzzy extractor technology is proposed, and the analysis show that the proposed scheme is more security and efficient than other related schemes.